CVE-2021-27137（dd-wrt dd-wrt）の深刻度・悪用状況・対象バージョン
8.1 重要（CVSS 3.x） 悪用確認済み（CISA KEV） EPSS 取得中…
概要
An issue was discovered in router/upnp/src/ssdp.c in DD-WRT before 45724. An unsafe strcpy in the UPnP handling functionality allows an unauthenticated remote attacker to send a request that would overflow an internal fixed buffer. Exploitation requires the DD-WRT user to enable UPnP (which is off by default, and only listens on internal interfaces by default). This occurs in ssdp_msearch (reachable by an M-SEARCH request).
実際の攻撃で悪用されています。 CISA KEV への追加日: 2026-07-21。対象製品を使っている場合は最優先で対策してください。
CISA の要求対応: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA の要求対応: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
影響を受ける製品
| ベンダー | 製品 | 対象バージョン |
|---|---|---|
| dd-wrt | dd-wrt | < 45724 |
基本情報
- 公開日
- 2026-07-16
- 最終更新
- 2026-07-22
- NVD の状態
- Analyzed
- 弱点の種類
- CWE-121
対策の進め方
- 上の表で、使っている製品とバージョンが対象か確認します。
- ベンダーの公式アドバイザリ（下の参考情報の「Vendor Advisory」「Patch」）で修正版・回避策を確認します。
- 悪用が確認されているため、パッチ適用までの間もアクセス制限・侵害の痕跡確認を検討します。
- 日本語の情報は JVN iPedia で CVE-2021-27137 を検索 できます。
参考情報
- https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.html ExploitThird Party Advisory
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/ ExploitThird Party Advisory
- https://svn.dd-wrt.com/changeset/45724 Patch
- https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/ ExploitThird Party Advisory
- https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmo Exploit
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/ ExploitThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27137 US Government Resource
- NVD: CVE-2021-27137
- CVE.org: CVE-2021-27137
データ出典: NIST NVD、CISA KEV、FIRST EPSS。翻訳は参考情報で、正確性は原文を優先してください。